Yū lives within a massive housing complex plagued by terrifying and mysterious events involving a life form called Ghost Bugs. As a central character, Yū experiences the unfolding horror alongside Rin, another resident who becomes pivotal to the narrative. Their lives intertwine under the complex's oppressive atmosphere, filled with eerie occurrences and unexplained phenomena. Yū encounters supporting characters like the Landlady and the Maintenance Man, figures integral to the complex's operations and the broader mystery. Navigating the escalating threats posed by the Ghost Bugs, Yū confronts manifestations that form part of a larger, interconnected terror within the setting. Yū's background prior to residing in the complex remains unexplored. Development across the narrative centers on reactions to the supernatural events, not explicit personal growth or history. Interactions with other residents and entities drive Yū's involvement in confronting the horror, though specific internal changes or arcs are not detailed. Yū's role is confined solely to the events within the housing complex as depicted in the combined narrative of the films. No additional backstory, development, or appearances in other media such as spin-offs, prequels, or sequels are documented.